Dr. Silliman is a geriatrician and clinical epidemiologist whose research most broadly described, has focused on chronic disease management in older adults. Over the past fifteen years, her breast cancer studies have been the core of this work. They have identified aspects of patient-physician communication as important factors in treatment decision-making, even after tumor characteristics, comorbidity, and functional status are taken into account. Dr. Silliman's investigative work has also explored alternative methods of comorbidity measurement and has considered the implications of treatment variations for a range of health outcomes: (1) general and breast cancer-specific emotional health; (2) upper body function; and (3) breast cancer recurrence and mortality. Dr. Silliman has also added to the small but growing body of observational study evidence that suggests that variations in breast cancer treatment do influence rates of breast cancer recurrence and mortality. Her currently funded R01 is designed to: (1) compare the effectiveness of adjuvant tamoxifen therapy, versus no adjuvant tamoxifen therapy, in reducing breast cancer recurrence and breast cancer mortality rates among older women receiving recommended definitive primary tumor therapies and those not receiving such therapies; (2) quantify the prevalence of tamoxifen discontinuance and identify patient and physician characteristics associated with it during the recommended five years of therapy; and (3) identify risk factors associated with a decline in health- related quality of life outcomes, particularly upper body function, during five years after breast cancer diagnosis. Dr. Silfiman's specific career objectives for the proposed award are: (1) to provide scientific evidence about breast cancer care and its consequences in older women, especially those > 75 years of age; (2) to apply new analytic techniques to existing data to control for confounding and misclassification in observational studies of breast cancer treatment; (3) to develop the research database infrastructure to study age-related variations in cancer treatment and outcomes among older cancer patients, applying the methods and experience developed studying breast cancer in older women to other common cancers (e.g., lung, colerectal, and prostate cancer) and, (4) to develop young clinical and non-clinical investigators whose research will focus on cancer prevention and control in older persons.